This invention relates to the synthesis of cyclic nitrogen compounds. In particular, the invention relates to the synthesis of N,3,4-trisubstituted-3-azoline-2-ones, (also known as 1,5-dihydro-1,5,N-trisubstituted-2-H-pyrol-2-ones).
N,3,4-trisubstituted-3-azoline-2-ones are useful as central nervous system drugs and as pharmaceutical intermediates.
U.S. Pat. No. 3,272,842 (Easton - Eli Lilly, 1966) describes the synthesis of related compounds by the cyclization of N-acyl derivatives of .beta.-keto amines in the presence of a strong base in a solvent.
GB 2,028,307 (Hofer - Mundipharma, 1980) teaches the synthesis of related compounds by the ring closure of an N-aroylmethyl acetamide in basic media under nitrogen.